Greenhouse gas dynamics of an increased use of wood in buildings in Switzerland

Long-living wood products contribute to the mitigation of climate change in many ways. They act as a carbon pool during their service life, as they withdraw CO2 from its natural cycle. After their service life, they can substitute for fossil fuels if they are incinerated in adequate furnaces. Furthermore, wood products can stitute for more energy-intense products made of 'conventional' materials. This paper quantifies the stitution and pool effects of an increased use of wood in the building sector in Switzerland for the years 2000-2130. Life cycle data on greenhouse gas (GHG) emissions of 12 wood products and their substitutes are used as proxies for relevant building products; this data is linked to the forecasted wood flows for each group of building products in a cohort-model. For the political assessment, GHG effects occurring abroad and in Switzerland are distinguished. The results show that the pool effect of an increased use of long-living wood products is of minor importance, whereas the energetic and material substitution effects are much more relevant, especially on a long-term. For construction products, the Swiss share of the GHG effect related to the material stitution is relatively high, as mainly nationally produced materials are substituted for. For interior products, the Swiss share of the GHG effect related to the material stitution is rather small because mainly imports are substituted for. The results must be considered as rough estimates. Nonetheless, these calculations show that an increased use of wood in the building sector is a valid and valuable option for the mitigation of greenhouse gas emissions and for reaching GHG emission targets in a mid- to long-term. Still, the pool and stitution capacity of an increased use of wood is relatively small compared to the overall GHG emissions of Switzerland.